Field of the Invention
The present invention relates to a membrane electrode assembly manufacturing apparatus which forms an electrode layer on a surface of an elongated strip-shaped electrolyte membrane while transporting the electrolyte membrane.
Description of the Background Art
In recent years, attention has been given to fuel cells as power sources for driving motor vehicles, mobile phones and the like. A fuel cell is a power generation system that generates electric power through an electrochemical reaction between hydrogen (H2) contained in a fuel and oxygen (O2) in the air. The fuel cell has advantages over other cells in its high power generation efficiency and low environmental load.
There are several types of fuel cells that are different depending on electrolytes being used therein. One of these fuel cells is a polymer electrolyte fuel cell (PEFC) including an ion exchange membrane (electrolyte membrane) used as the electrolyte. Polymer electrolyte fuel cells, which are capable of operating at room temperature and can be reduced in size and weight, are expected to be applied to motor vehicles and portable devices.
In general, the polymer electrolyte fuel cells have a structure such that multiple cells are stacked one on top of another. One cell is comprised of a membrane electrode assembly (MEA) and a pair of separators provided on opposite sides of the membrane electrode assembly to sandwich the membrane electrode assembly therebetween. The membrane electrode assembly includes an electrolyte membrane and a pair of electrode layers formed on opposite surfaces of the electrolyte membrane. One of the two electrode layers is an anode electrode, and the other thereof is a cathode electrode. When a fuel gas containing hydrogen comes in contact with the anode electrode and air comes in contact with the cathode electrode, electric power is generated through an electrochemical reaction.
The aforementioned membrane electrode assembly is typically produced by applying a catalyst ink (electrode paste) to a surface of an electrolyte membrane and then drying the catalyst ink. The catalyst ink is obtained by dispersing catalyst particles containing platinum (Pt) in a solvent such as alcohol. A conventional technique of manufacturing such a membrane electrode assembly is disclosed, for example, in Japanese Patent Application Laid-Open No. 2013-161557.
In a manufacturing apparatus disclosed in Japanese Patent Application Laid-Open No. 2013-161557, an electrolyte membrane is held on an outer peripheral surface of a sucking roll, with a porous base material therebetween. While the porous base material and the electrolyte membrane are transported by rotating the sucking roll, a catalyst ink is ejected from a nozzle, so that the surface of the electrolyte membrane is coated with the catalyst ink. In such a manufacturing apparatus, multiple base materials are transported to and from the sucking roll. Accordingly, multiple rollers are disposed around the sucking roll.
The nozzle for ejecting the catalyst ink and piping require maintenance such as cleaning in a disassembled state at regular time intervals. This involves the need to ensure not only the multiple rollers but also space for maintenance around the sucking roll.